X is for XOR
by shaolingrrl
Summary: Written for the 2007 Summer Alphabet Challenge


Post-ep for "The Janus List" with attendant spoilers.

I don't usually hassle folks for reviews but I would like to hear what you think of this one. It's got less plot than I'm comfortable with. On the other hand, I wanted to try less plot. I'm thinking it all translates to too long for what it is. Plus there's a section that I feel is kind of cheesy...

I forgot the disclaimer last time. I hope I did not lead anyone to believe with my last story that I am the Secret Mistress of Numb3rs. And I'm not the Secret Mistress of Numb3rs with this story, either.

**X is for XOR**

Don Eppes stands outside his younger brother Charlie's office and studies the message on his cell phone display. DON NEED HELP IM AT CALSCI. Don worries his lower lip with his teeth. This text message is quick and to the point. While Charlie can come to the point, he's seldom quick about it and he prefers to talk.

Don wishes he wasn't so tired. If Charlie needs help he wants to give it, but the first round of post-Colby interviews (interrogations) are finally over and Don is feeling the effects. Two weeks worth of twelve-hour days going over Colby's every case in exhaustive detail, his every report, every official mention of his name, followed by nights spent on the couch staring at whatever's on the classic movie channel. His stomach has been too tied up in knots to eat much, and he's pretty sure he's not of much use to anybody right now.

Don hits a speed-dial button but hears no answering ring from inside the office. His call goes straight to voicemail. The sensible action--the action of FBI Special Agent Don Eppes--would be to walk in, pluck a handful of darts from the board, and calmly keep himself occupied until Charlie gets back, but Don hesitates.

Maybe he should leave a message for Charlie saying he'll show up when he can and go back to David and Megan, begin the long and painful process of picking up the pieces. But Don's not sure he knows how. He doesn't know where Megan's sweetness and warmth are, or how to give David back his smile.

He could at least drag them to some quiet, dim bar for happy hour and reminiscing, but they don't have too many good times together that don't include Colby. Don knows that if he asks, both Megan and David would turn him down.

So why does he still feel like a coward?

He flips his phone shut and walks into Charlie's office.

Charlie isn't there. His books are--piled three and four deep on his desk, the worktable, the tops of the bookshelves. The chalkboard is covered with scribbles, the filing cabinets are buried under toys and files, and the late afternoon sun is drenching everything in a warm, buttery light. The whole scene is so--normal that Don's hit by a sense of unreality strong enough to dizzy him. He grabs for the door frame.

Don shakes his head to clear it and pulls himself into the room. He's fought damned hard to keep Charlie out of his mess, to present his brother as just another consultant who deals mostly with him and barely knows Colby at all, and so far it's been working. He should be glad to see the normalcy around him.

Nothing in the room explains Charlie's problem, though. Don frowns at the chalkboard. Charlie's problems are usually captured right there, meaning Don usually can't understand them.

He scrubs at his mouth. Maybe this time...there. In the upper right corner he sees the letters "XOR" written in caps and boxed in. Two arrows diverge from the box. The letters look like a suffix from that hacker language, leetspeak, but the word they modify has been erased.

He makes his way up to the board, breathes in the slightly sweet scent of chalk dust, reaches up to draw his own box around the letters with a forefinger. Is this what's going on? Charlie's consulting on some (not his) hacking case?

"Exclusive or," says Charlie from the doorway, and Don spins around so fast spots dance in front of his eyes. He automatically widens his stance and blinks, trying to clear his vision.

"Don?"

Don hears concern, but nothing more. No underlying tension, nothing to indicate that Charlie's under any pressure. He pulls Charlie's face into focus and his impression is confirmed. Charlie's eyeing him with a worried frown, but his brother looks rested, looks like he's eating, and the relief that floods through Don almost makes him stagger again. "What? Exclusive what?"

"Exclusive or." Charlie approaches him slowly, like he's afraid Don will spook. "It's a--a Boolean thing. P can be true, or Q can be true, but not both. Why don't you sit down, Don?"

"Not a hacking case?"

Charlie redirects his frown from his brother to the chalkboard, then his face clears and he grins. "Oh! Like haxor or suxxor. Nope, just XOR." He's finally close enough to take Don's arm and tug him gently toward a chair. Don decides to let him have his little victory. "I'm helping Amita code a simulator for brown dwarf formation. We're having a few problems with it, but the XOR is just a place where it branches." He turns Don around, applies pressure to his shoulders, and Don's knees give. He sits. When did Charlie start with the secret ninja training?

"That can't be why you need me."

Charlie pulls up another chair and fixes Don with an intent look. Don tries to gather his wavering thoughts. He wants to help Charlie, he wants to not feel like a screw-up for maybe ten minutes, but he's so tired--

"What I need," says Charlie, "is to take you home, feed you a decent meal, and put you to bed. Dad's feeling the need for something pretty similar, by the way. He said to pass that on."

Don gapes at him.

"So where'd you park? We'd better take your car--mine's got a faculty parking sticker on it so I can leave it overnight. And where are your keys? I'll drive. You're not driving, that's for sure."

"You need what?"

Charlie flinches at the volume but recovers quickly and his mouth settles in a mulish line. "Don, we haven't seen you in two weeks. Not since--"

"I know what happened two weeks ago."

"Yeah, well, you haven't called, and Dad's been worried sick--for good reason, apparently. I can't even find out what's going on."

"For good reason," Don snaps. "Apparently."

Charlie sits back and studies him. "So, Don. Why haven't I been called in to answer questions?"

Don stares blindly at the chalkboard.

"You're protecting me again, aren't you."

Don pushes himself to his feet. He's glad he only needs to lean on the desk for a few moments before the black spots are gone.

"Dammit, Don." Charlie doesn't yell. He sounds more tired than anything. "I can't believe we're having this discussion again. Not after everything that's happened."

"Look, Charlie, the office is not a good place to be right now. And I'm not a good person for anyone with a security clearance to be around. Even Liz figured that one out."

He hears Charlie gasp, feels a hand on his sleeve. "God, Don. I'm so sorry. But seeing you is not fraternizing with the enemy. You're my brother. That's what the word means."

Don shakes him off and takes a step toward the chalkboard. He hears anger and disappointment, and he doesn't want to face them. "You've got a lot of other consulting gigs with a lot of other agencies, you know. Even other teams at the FBI, if you want. You should be concerned with letting this (me) drag you down. Don't you think--"

"No," Charlie yells. "No, I don't think. I'm not allowed to think. Apparently you don't believe I'm capable of thinking."

"Charlie, that's not it and you know it." Don's about to turn, but he sees the little box with the letters "XOR" inside and stops. What did Charlie call it? Exclusive or. One side is right, or the other side is right, but both sides can't be right.

Don turns and walks out.

An indeterminate amount of time later, he ends up at the turtle pond. They're not koi, but that's okay. He can't face his apartment, Liz accepted his suggestion that they cool it for a while with stinging speed, and as much as he loves his father, he's not sure he can face any more questions--even unspoken ones--right now. He'd thought that left Charlie; after everything that's happened, Charlie should understand.

Don shrugs. Next to the turtles is as good a place as any.

After everything that's happened--

Don closes his eyes, determined this time not to shy away from the nightmare vision that's been dogging him for the last two weeks. He sees Charlie push Ashby in the hospital bed, he can feel his heart pound like Charlie's must have pounded. Charlie's running from an assassin and all Don can do is watch.

He forces himself to stay with it, watching Charlie as his brother looks back over his shoulder, terrified that a man with a gun is going to appear in the corridor at any moment. He sees Charlie spot the sign for the MRI, a sign that would have meant nothing to him, and wheel Ashby inside the room. Then--

Then, even with his body so tired and worn that his pounding heart makes him feel dizzy and sick, Don watches Charlie trap the killer, and he can't help but be proud of his brother's courage and quick thinking.

Of course, when it's over Charlie starts analyzing. Why did he risk his life for a dying man?

And what does Charlie decide? A mind like Ashby's is worth the risk.

A mind like Ashby's--brilliant, like Charlie's--

His little brother.

Don drags his eyes open and pries his fingernails out of his palms. "Yeah, Charlie," he whispers. "After everything that's happened."

After everything that's happened, Charlie should get at least part of why Don fights to protect him.

After everything that's happened Charlie should get at least part of why he's worth it.

Instead, Don gets, "I can't believe we're having this discussion again."

You're both right, Donnie.

Don jerks his head up. For a moment he can feel his father standing behind him, hands on his shoulders. But the words Don heard weren't spoken in the reassuring tone his father had used two weeks ago--they were more a gentle remonstrance, spoken in Alan's "Father Knows Best" voice.

"I'm more right than he is," Don mutters.

"Delirium setting in?"

Charlie sinks down on the other end of the bench. If not for the voice and the silhouetted hair, Don wouldn't know who it is. He starts. The sun's down, with full dark not far behind. A cool breeze fingers the back of his neck. "Hey."

"Hey."

"How'd you find me?"

Charlie snorts. "You're wearing a suit. You scream 'Fed'. Five students and two other faculty members have stopped by my office in the past hour and a half to tell me my brother's sitting by the turtle pond."

"Get out."

"No, really. Two of the students wondered if they should have called an ambulance."

It's Don's turn to snort.

"You look like crap, Don. You're shivering."

"It's cold."

"You're so worn down you're making yourself sick." Charlie scoots closer and his voice softens. "Let me take you home."

It's too dark to see the turtles, so Don studies his hands instead. "Hear me out first."

"You don't have to apologize."

"I'm not going to apologize, Charlie." He looks up and it's not too dark to see Charlie's expression: cautious, a little annoyed.

"You're not going to apologize?"

"No."

"Wait--don't you think you should?"

"Shut up, Chuck." Don takes a deep breath and scrubs both hands through his hair. "Yes, I've been trying to protect you. But not because I think you can't take care of yourself. You've proven you can by now."

"Then why?"

"Because I want to, Charlie, that's why. Because I--" but Don's either too tired or not tired enough to follow that one where it's headed, and he looks down again. "I want to, and that's all there is to it. And just so you know, I don't see that changing any time soon. I'm sorry."

Silence. "Okay, then," Charlie finally breathes. Don risks another look at his brother and it's never too dark to see that smile. "Okay. I want to take you home and feed you a decent meal and put you to bed, and Dad wants the exact same thing. So where does that leave us?"

Don fishes his keys from his pocket and hands them over.

"Good answer, bro."

"Wait." Don stops Charlie with a hand on his arm. "Did you finish that problem you were working on for Amita?"

"Not yet, but I'd rather it still be here in the morning than you. Let's go, G-Man."

Don resists Charlie's tug. "You should check that 'XOR' thing. That exclusive or."

"Why? It's just a branch." But Charlie drops back onto the bench next to him and studies his face. Maybe what happened with the G Major scale is making Charlie think twice about dismissing Don's hunches. He turns and stares out across the pond. "I mean, the Jeans Limit is the Jeans Limit, isn't it?"

Are they discussing Charlie's wardrobe now?

Charlie stiffens and hisses out a long breath. "Except for when the collapsing molecular cloud is on the tail end of a burst of star formation. Then it's going to get blasted by so much radiation-- Or maybe a supernova--" He turns to Don and claps him on the shoulder. "You're right. A simple branch is already completely insufficient by that point."

Don tries not to look lost.

"I'm embarrassed. Amita's not usually this sloppy and I'm not usually this clueless."

"You've both been a little distracted lately."

"Yeah." Charlie sobers, but it doesn't take long for an impish grin to reappear. "I can't wait to tell her that you figured it out, though."

"Why? Because that'll make her feel even more stupid? Gee, thanks."

"And maybe I'll push to have your name added to any papers that come out of this." Charlie's grin widens. "Wouldn't that be great? To be listed on a paper together? I'll still be first, though, because 'Eppes, C.' comes before 'Eppes, D.'."

"Charlie--"

Charlie sinks back and nudges Don's shoulder with his own. "So what made you think of the exclusive or?" He's trying to sound casual but Don can tell the whole phenomenon of his big brother horning in on his hunches has Charlie a bit rattled.

Don shrugs. "It's never worked for us."

Charlie sucks in his breath. He nods once, then stands and offers Don a hand. "Come on, genius," he says softly. "Let's get you home."


End file.
